Abstract
Separation vortices are generated at the tip of a cape exposed to a tidal current perpendicular to the major
axis of the cape. The boundary layer thickness increases with increasing distance along the cape. Vortices are
generated when the flow separates at the tip of the cape. An upwelling is generated due to the spin down of this
separated vortex. This study examines the generation period and the strength (circulation) of the separated vortex
by means of hydraulic experiments. The experimental results show that the Strouhal number is constant and does
not depend on the Reynolds number when the flow condition is higher than a Reynolds of 300. The formation
process of separated vortices is visible by these experiments. The strength of the separated vortex is related to
the vorticity at the separation point. This vorticity is govemed by the headland length, the current velocity and
the Strouhal number. A theorem is proposed to describe the boundary layer development along a cape in which
the boundary layer thickness increase along the cape is proportional to the headland length. This theorem shows
good agreement with the experimental data.
